CT SCAN PROCEDURES IN CHILDREN IN
FRANCE OVER THE PERIOD 2012–2018 AND
ASSOCIATED RADIOLOGICAL EXPOSURE
ADDENDUM TO IRSN REPORT /2020-00564 ENTITLED“EXPOSURE OF THE POPULATION TO IONISINGRADIATION FROM DIAGNOSTIC MEDICAL IMAGING
PROCEDURES IN FRANCE IN 2017”(EXPRI 2017 REPORT)

1

IRSN – CT SCANS IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

FRENCH PUBLIC EXPERTIN NUCLEAR AND RADIOLOGICALRISKSAssessing, researching, protecting, anticipating,and sharing are the missions of IRSN in the serviceof the public authorities and the public.
The uniqueness of the Institute lies in its ability tobring together researchers and experts toanticipate future issues relating to evolution in andcontrol of nuclear and radiological risks.
IRSN’s employees are committed to making theirwork known and sharing their knowledge withsociety. In this way, they contribute to improving
access to information and dialogue withstakeholders.
The Institute contributes to public policies on
nuclear safety and security, health, environmentand crisis management.
As a public industrial and commercial
establishment (EPIC) under the joint supervision of
the Minister of the Environment, the Minister ofDefence, and the Ministers of Energy, Research,and Health, IRSN actively promotes the State’s
modernization policies with its risk management
approach and the implementation of a global social
responsibility policy.

THE
INSTITUTE
HAS ABOUT

EMPLOYEES
including manyengineers,
physicians,
agronomists,
veterinarians,
technicians,
experts andresearchers

2

To carry out its
missions, IRSN has

A BUDGET OF
APPROXIMATELY

270 M€IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

ABSTRACTThis report, produced by the French Institute forradiation protection and nuclear safety (IRSN),
completes the "ExPRI 2017" study on the
exposure to ionising radiation of the general
population during diagnostic procedures in France
in 2017. It describes the exposure of children
under 16 during CT (computed tomography)
procedures in France in 2012-2018. The study was
based on procedures extracted from the“échantillon généraliste des bénéficiaires” (sample
of persons who are protected by a healthinsurance in France), representative of 1/97 of theFrench population.
Over the period studied, the annual frequency ofCT procedures is relatively constant (all ages andsexes combined) and fluctuates around an
average of 13.7 ‰.
On average over this period, the frequency of CT
procedures per year is highly variable according to
the age of the child: around 15 ‰ for children
under 1, less than 10 ‰ for those between 1 and9, then it increases rapidly to reach more than 35‰ at 15 years old. Furthermore, the frequency ofCT procedures is significantly higher in boys thanin girls but with the same trend according to age.
In terms of anatomical area explored in CT, headand neck procedures are the most frequent (about
60 %). Overall, the proportion by anatomical area
explored in CT is stable over the period studied. As
CT and MRI (magnetic resonance imaging) have alarge number of common indications and as therecommendations of professionals (in particular
those of the French society of pediatric andprenatal imaging (SFIPP)) are moving towards atransfer to MRI of certain procedures (cerebral
exploration for example), a study of the evolutionof MRI procedures was also carried out.
This study shows that, contrary to the CT, theannual frequency of MRI procedures increases
significantly (+59 %) over the period studied andthe frequency is higher for girls.
As in CT, head and neck procedures are the mostfrequent in pediatric MRI, with a proportion
between 40 % and 45 % of procedures, relatively
stable over the period studied. Limb procedures
come in second place, with a proportion between
35 % and 40 %.
Over the period studied, the proportion of children
having had at least one CT scan (exposedchildren) per year considered is relatively stable, at
1.1 % for all ages combined, with an average of
1.23 scan per exposed child. Among thispopulation of children, between 11 % and 16 %had 2 or more CT scans depending on the year
considered.
According to the pediatric data analyzed in the
Diagnostic Reference Levels (DRL) systemmanaged by IRSN, the doses received by children
for a CT scan (for the brain, abdomen-pelvis andchest) show a decreasing trend between 2011-12
and 2016-18. However, due to the small amount ofdata collected during these periods, this decrease
should be considered with caution. The new orderof 23 May 2019 on DRL has included the obligationfor establishments to send pediatric dosimetricdata when more than 5 % of procedures on a given
medical device concern pediatrics. This regulatorychange has made it possible to obtain more datain pediatrics over the period 2019-2021. Their
analysis, in the next DRL report to be published,
will provide more precise information on theionising radiation doses received by children.

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

3

SUMMARY
ABSTRACT .........................................................................................................................3
1.

CONTEXT ...................................................................................................................5

2.

MATERIALS AND METHODS ....................................................................................6
2.1

THE GENERALIST SAMPLE PANEL OF HEALTH INSURANCE BENEFICIARIES (EGB) 6

2.2
IDENTIFICATION OF PROCEDURES: THE COMMON CLASSIFICATION OF MEDICAL
PROCEDURES (CCAM) ......................................................................................................................... 6

3.

2.3

COUNTING PROCEDURES .................................................................................................... 6

2.4

STUDY METHOD AND CHARACTERISTICS ......................................................................... 6
2.4.1

Data analysed .................................................................................................... 6

2.4.2

Technical characteristics for the extraction of data of interest ................... 7

2.4.3

Quantity used: procedure frequency (per 1,000 individuals)....................... 7

QUANTITATIVE EVOLUTION IN PAEDIATRIC CT SCAN PROCEDURES IN
FRANCE OVER THE PERIOD 2012–2018.................................................................8
3.1

CT SCAN PROCEDURE FREQUENCY IN THE PAEDIATRIC POPULATION ..................... 8
3.1.1

Average frequencies over the period 2012–2018 .......................................... 8

3.1.2

Evolution in CT scan procedure frequency over the period 2012–2018 ..... 9

3.1.3
Comparison with the evolution in MRI (magnetic resonance imaging)procedure frequencies ......................................................................................................... 10
3.2

4.

3.2.1
studiedEvolution in the distribution of CT scan procedures over the period.......................................................................................................................... 12

3.2.2

Comparison with evolution in the distribution of MRI procedures ........... 13

EVOLUTION IN THE TOTAL NUMBER OF CT SCANS PER CHILD OVER THE
PERIOD 2012–2018 ..................................................................................................16
4.1

4.2

5.

DISTRIBUTION OF CT SCAN PROCEDURES BY ANATOMICAL AREA .......................... 12

PROPORTION OF CHILDREN EXPOSED TO A CT SCAN ................................................. 16
4.1.1

Proportion, all ages ........................................................................................ 16

4.1.2

Proportion by age group ................................................................................ 16

4.1.3

Number of CT scan procedures per patient................................................. 17

PATIENTS WHO HAD AT LEAST TWO CT SCAN PROCEDURES IN ONE YEAR ........... 17

EVOLUTION IN CT DOSE INDICES FOR CHILDREN OVER THE PERIOD 2012–2018 ..........................................................................................................................19

CONCLUSION ...................................................................................................................21
GLOSSARY.......................................................................................................................22
REFERENCES ..................................................................................................................23
TABLE OF ILLUSTRATIONS AND TABLES ...................................................................24

4

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

1. CONTEXT
The risk of long-term effects such as cancer from exposure of children to medical ionising radiation has beenan active research topic for many years. As CT scan procedures are among the most irradiating diagnostic
procedures, they have been the subject of particular interest and a large number of publications. Since the late
1990s, several of these publications, such as that of Brenner in 2001 [1], have reported excess numbers ofcancers in the paediatric population based on excess risk calculations. At low doses, the dose-response
relationship considered in several reports, such as BEIR VII (Biologic Effects of Ionizing Radiation, 7th report)[2] and ICRP publication 1031 [3], is the linear no-threshold model. As the use of this model is regularly
questioned in the light of advances in epidemiology and radiobiology (see report from the Nuclear Regulatory
Commission [4], for example), these figures have been hotly contested. However, during the last decade,several epidemiological cohort studies dedicated to childhood exposure to CT scan procedures have been
published ([5]–[10]). Most of these studies only look at the risk of brain tumours and leukaemia. For these two
types of cancer, the results show a statistically significant excess risk overall, although the number of cancer
cases remains low. As for other cancer locations, only the study by Mathews et al [6] considers these, theother studies having too few cancer cases for an analysis.
In addition, there are potential confounding factors in the above studies that may bias the results by attributing
the occurrence of cancers to exposure to CT scans, whereas the cancers may be related to genetic or otherconditions predisposing individuals to the occurrence of cancers, these underlying conditions being the very
reason the scans were performed. In addition, uncertainties in dosimetric reconstruction may also impact thedose-response estimate.
It was in particular to try to take into account these potential methodological limitations that the European EPICT study2 was launched in 2011. By combining 9 national cohorts (Belgium, Denmark, France, Germany,
Great Britain, the Netherlands, Norway, Spain and Sweden), more than one million patients were included inthis meta-cohort. The follow-up covered the period 1990–2013 (this period varies from country to country,
generally starting between 1990 and 2000 and ending in 2013). Numerous precautions were taken to minimise
potential bias due to these confounding factors. The results of this study are expected to be published in the
coming months.
The majority of children included in the EPI-CT study had CT scans in the decade 2000–2010 and inclusion
ended in 2012. However, the technology of these medical imaging devices has improved significantly sincethen, leading to a reduction in the dose delivered.
This report, prepared by the Institute for Radiation Protection and Nuclear Safety (IRSN), looks at evolution in
the number of CT scan procedures performed on the French paediatric population between 2012 and 2018,the most recent data available in the national health data system (SNDS) at the time the report was written. It
is an addendum to the previous ExPRI report (ExPRI 2017 [11]), which presented the exposure of the general
population to ionising radiation due to diagnostic procedures for the year 2017 only, focusing on evolution over
several years in CT scan procedures for children.

1
2

International Commission on Radiological Protection“Epidemiological study to quantify risks for paediatric computerized tomography and to optimise doses” https://epi-ct.iarc.fr/
IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

52. MATERIALS AND METHODS
To carry out this study, IRSN relied on data available in the generalist sample panel of health insurance
beneficiaries accessible via the secure portal of the SNDS of the French Health Insurance Body (CNAM). As
each medical procedure is associated with a specific code, it is possible to carry out the necessary queries tostudy the evolution in the number of paediatric CT scan procedures over a defined period.

2.1 THE GENERALIST SAMPLE PANEL OF HEALTH INSURANCEBENEFICIARIES (EGB)The SNIIRAM decree3 of 20 June 2005 made it possible to create a national sample representative of 1/97 of
the beneficiaries of the health insurance scheme (general scheme excluding local healthcare mutual sections),
in terms of age and sex, called the generalist sample panel of health insurance beneficiaries (EGB). This is apermanent sample of beneficiaries, linking their administrative and socio-demographic characteristics to their“consumption” of care over time (this consumption may be equal to zero).
EGB data is accessed via a secure CNAM internet portal. Since the end of 2016, IRSN has had permanent
access by decree [12] as part of its public service missions, and in particular for writing of the periodic reporton the exposure of the population to ionising radiation due to diagnostic medical imaging procedures (EXPRI
report) and its addenda.

2.2 IDENTIFICATION OF PROCEDURES: THE COMMON
CLASSIFICATION OF MEDICAL PROCEDURES (CCAM)The CCAM is a single coded reference system for all technical medical procedures covered by the national
health insurance system. Its use is national and compulsory since 31 December 2005 for all generalpractitioners and specialists practising either in the outpatient sector (local practices, health clinics, etc.) or in
the public or private hospital sector (hospitalisations and outpatient consultations). These codes are used for
pricing and activity descriptions.
The CCAM ensures that diagnostic procedures are unambiguously identified from one another. Each type ofprocedure is identified by a complete description and a code composed of four letters and three digits: forexample, the CCAM code ACQK001 corresponds to the description “CT scan of the skull and its contents,
without injection of contrast”.

2.3 COUNTING PROCEDURES
The consumption of care by each beneficiary is periodically entered in the EGB using billing data from the
SNIIRAM. Since June 2011, the SNIIRAM has included reimbursement data for healthcare services (outpatientcare) as well as public and private hospital data, thanks to the integration of additional data from the PMSI
(Programme de médicalisation des systèmes d’information [Programme for the Medicalisation of Information
Systems]) of the ATIH (Agence technique de l’information sur l’hospitalisation [Technical Agency for
Information on Hospitalisation]). The CCAM is used to code the procedures performed. As each beneficiaryincluded in the EGB is identified by his or her encrypted NIR4, it is therefore possible, while respecting theanonymity of the patients, to reconstruct the care pathway, whether it was carried out by a professional
practising in the private or public sector and whether it took place in a practice or in hospital.

2.4 STUDY METHOD AND CHARACTERISTICS
2.4.1 Data analysed
The data analysed in this study are taken from the extraction of all CT scan procedures performed on children
under 16 years of age (at the time the procedure was performed, to the nearest month) and recorded in the
EGB from 2012 to 2018.
The data are processed independently year by year in order to estimate the variation of the different indicators
over the whole period studied.

3

Système national d’information interrégimes de l’Assurance maladie (French inter-regime health insurance information system)

4

Numéro d’inscription au répertoire national des personnes physiques (Registration number in the national register of natural persons,the social security number)

6

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

Only beneficiaries of the general regime (RG), the social regime for the self-employed (RSI) and the agriculturalsocial insurance mutual benefit fund (MSA) are included. Beneficiaries of local healthcare mutual fund sections(SLM), which were only gradually integrated into the EGB from 2015 onwards, are not taken into account. This
choice avoids introducing an artificial bias in the annual comparisons by keeping the representativeness of the
EGB in relation to the general population constant over the period 2012–2018.
The population considered was studied in 5-year age groups (or by year when the information was relevant),in accordance with the recommendations of European report No. 154 [13], with a specific group for children
under one year old, given the particular morbidity of this age group.

2.4.2 Technical characteristics for the extraction of data of interest
Queries were carried out using the SAS Enterprise Guide 7.1 software on the databases of the national healthdata system (SNDS) to extract the EGB CT scan procedures performed over the years 2012–2018, as well as
data relating to the beneficiaries (sex and age at the time of the procedure).
In practice, as the day of birth of the beneficiaries is not available in the EGB to avoid any re-identification, theage of the beneficiaries at the time of the diagnostic procedure is calculated to the nearest month, then roundedup. For example, a child born in February 2016 and having a radiological procedure in February 2017 is
considered to be 12 months old at the time of the procedure, whereas their real age may be 11 or 12 months
depending on whether the day of the procedure is before or after their birthday.
Paediatric procedures extracted include:•

procedures performed in the private sector, i.e. by practitioners in private practices, full-time hospital
private practitioners, as well as practitioners working as a salaried employee in a privately-funded
institution, which therefore includes procedures performed in local practices and in private healthcare
institutions (during hospital stays or outpatient care);•procedures performed during hospital stays in public healthcare institutions;•procedures performed during outpatient care in public healthcare institutions.

For each of these procedures, the parameters of interest for this study were:•

the demographic characteristics of the beneficiary: encrypted NIR, sex, month and year of birth;•the characteristics of the procedure:– the care sector (private, public inpatient and outpatient);– the CCAM code and the description of the procedure;– the month and year it was performed.

2.4.3 Quantity used: procedure frequency (per 1,000 individuals)
Procedure frequency is defined as the number of CT procedures performed annually in a given population.
For example, if in a population of n children aged 6 to 10 years old, m scans are performed during one year,𝑚the procedure frequency F, expressed per 1,000 individuals, will be 𝐹 = × 1000 and is expressed in ‰. It𝑛should be noted that it is not taken into account whether the procedures concern the same individual or not.
All results presented in this report, unless otherwise stated, are expressed in procedure frequency. Thismethod makes it possible to avoid the influence of the age pyramid and differences by sex on the number ofprocedures. If the objective is to compare a number of CT scan procedures between boys and girls, thiscomparison must be carried out with constant numbers of boys and girls (for example 1,000 boys versus 1,000
girls). The same reasoning applies if the objective is to compare a number of procedures between two
populations of different ages.

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

73. QUANTITATIVE EVOLUTION IN PAEDIATRICCT SCAN PROCEDURES IN FRANCE OVER
THE PERIOD 2012–2018
3.1 CT SCAN PROCEDURE FREQUENCY IN THE PAEDIATRICPOPULATION
3.1.1 Average frequencies over the period 2012–2018
Overall, the frequency of CT procedures varied greatly according to the age of the child. Sex is also an
important factor, although less of a determining factor than age. For more details on this point, the reader may
refer to the paediatric ExPRI study published by IRSN in 2018 on data from 20155. Figure 1 below shows theaverage annual procedure frequencies observed between 2012 and 2018, according to the age of the child at
the time of the procedure. To clarify the meaning of Figure 1 below with an example: over the period 2012–2018, on average per year, about 9 CT scan procedures were performed on a population of 1,000 children 5
years old at the time of the procedure.

CT procedure frequency per year
(number of procedures per 1,000 individuals)

The frequency is slightly above 15 procedures per 1,000 children under 1 year of age, then below 10‰
and relatively constant until the age of 9. The procedure frequency then gradually increases to morethan 35 procedures per 1,000 children aged 15 years old.

Age in years

Figure 1: CT procedure frequency over one year (number of procedures per 1,000 individuals) according toage of the child (at the time of the procedure), on average over the period 2012–2018.
The CT scan procedure frequency also depends on the child’s sex, but to a lesser extent than on the child'sage. Figure 2 below shows that the CT scan frequency was higher for boys than for girls for all ages (except
15 years old, where it is almost equivalent). However, these differences remain moderate and the distributions
are fairly similar between the two sexes. To clarify the meaning of Figure 2 below with an example: on averageover the period 2012–2018, 10 CT scan procedures were performed per year in 8-year-old girls for a populationof 1,000 girls of the same age.

5

https://www.irsn.fr/EN/publications/technical-publications/Documents/IRSN_PSE-SAN-SER-2018-00004_2015-Expri-paediatricstudy_072019.pdf

8

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

CT procedure frequency per year
(number of procedures per 1,000 individuals)

Sex:

Boy

Girl

Age in years

Figure 2: CT scan frequency over a year (number of procedures per 1,000 individuals) according to the child’sage (at the time of the procedure) and sex, on average over the period 2012–2018.
The CT scan frequency varies greatly with the age of the child: from less than 10‰ between 1 and 9
years old, then more than 35‰ at 15 years old. It is worth noting the relatively high frequency inchildren under 1 year of age (about 15‰) and the significantly higher frequency in boys than in girls.

3.1.2 Evolution in CT scan procedure frequency over the period 2012–2018
Figure 3 below compares the annual procedure frequencies observed between 2012 and 2018 for thepaediatric population of all ages. To clarify the meaning of Figure 3 below with an example: in 2012, 12.5 CT
scan procedures were performed on girls out of a population of 1,000 girls under 16 years of age at the time
the scan was performed.
There is no clear trend in the overall procedure frequency (i.e. boys and girls combined): it is relatively
constant and fluctuates around an average value of 13.7 ‰. The frequency for girls was slightly lower(12.9‰) and also does not seem to have any clear trend over the 7 years studied. The procedure frequency
among boys was slightly higher and seems to have a slightly upward trend (+3.8% between 2012 and 2018).
A study of the evolution in procedure frequency by child age group (see Figure 4 below) showed significantly
different trends:•

the differences between boys and girls were smaller and the trend is similar for the age groups 1–5
and 6–10. In both groups, the trend is towards a slight decrease in procedure frequency;•

in the 11-15 age group, the differences between boys and girls tend to increase; a clear increase in
CT scan frequency for boys and a near stability for girls was observed;•

for children under one year of age, the frequency varied greatly from one year to the next, with noclear trend emerging. It should be remembered that these variations were probably due to statisticaluncertainty, since, on the one hand, the number of children under one year of age in the EGB isrelatively small (a few thousand), and on the other hand, the number of CT scans per year for thispopulation is very small (around 110 CT scans per year on average).

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

9Boy or girl

Boy

Girl

CT procedure frequency per year
(number of procedures per 1,000 individuals)

Sex:

Year of the procedure

Figure 3: Evolution over the period 2012–2018 in CT procedure frequency per year (number of procedures per
1,000 individuals) for girls, boys and both.

CT procedure frequency per year
(number of procedures per 1,000 individuals)

Sex:

B/G

B

G

Year of the procedure

Figure 4: Evolution over the period 2012–2018 in CT procedure frequency per year (number of procedures per
1,000 individuals) for 4 age groups (under 1 year, 1 to 5 years old, 6 to 10 years old, 11 to 15 years old), forgirls, boys and both.

3.1.3 Comparison with the evolution in MRI (magnetic resonance imaging)procedure frequencies
It is interesting to compare the evolution in CT procedure frequency with that of MRI procedures. These twoprocedures have many common indications and professionals (in particular the French Society of Paediatricand Prenatal Imaging (SFIPP)6) recommend a transfer to MRI of certain procedures (cerebral exploration for
example). Figure 5 below shows the annual MRI procedure frequency in children between 2012 and 2018,
overall (red curve) and for each sex (green and blue curves). Unlike with CT scans, the use of MRI showedvery clear growth: +59% growth over the period 2012–2018. The overall MRI procedure frequency, which
6

https://sfip-radiopediatrie.org/irm-encephale/

10

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

was significantly lower than that of CT scans in 2012 (10.6‰ vs. 13.3‰, respectively), exceeds the latterstarting in 2016 (13.8‰ vs. 15‰, respectively). However, the MRI procedure frequency for boys still remained
lower than that of CT scans in 2018 (14.4‰ vs. 14.9‰, respectively).

Boy or girl

Boy

Girl

MRI procedure frequency per year
(number of procedures per 1,000 individuals)

Sex:

Year of the procedure

Figure 5: Evolution over the period 2012–2018 in MRI procedure frequency per year (number of procedures
per 1,000 individuals) for girls, boys and both.
The evolution by age group, presented in Figure 6 below, showed some notable differences and similarities
with the evolution in CT procedure frequency:•

the MRI procedure frequency was approximately equivalent to that of CT procedures in the 1–5 and6–10 age groups. It has been significantly higher since 2015 for children under 1 year old andsignificantly higher since 2014 in the 11–15 age group;•

the increasing trend in MRI procedures is observed for all age groups, but is much more marked forthe 11–15 age group;•

the difference in frequency is in favour of girls for the 6–10 and 11–15 age groups, with a very marked
difference for the latter.

The CT scan procedure frequency has been stable overall since 2012. CT scans do not have the samechange trends as MRI scans for the paediatric population, particularly for older children. Overall, boys
have more frequent CT scans than girls, contrary to what is observed for MRI. This study of MRI
procedures was carried out because of the common indications with CT scans and the fact thatprofessional societies (in particular the SFIPP) are recommending a transfer from CT scans to MRI for
certain procedures (e.g. cerebral exploration).

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

11

MRI procedure frequency per year
(number of procedures per 1,000 individuals)

Sex:

B/G

B

G

Year of the procedure

Figure 6: Evolution over the period 2012–2018 in MRI procedure frequency per year (number of procedures
per 1,000 individuals) for 4 age groups (under 1 year, 1 to 5 years old, 6 to 10 years old, 11 to 15 years old),for girls, boys and both.

3.2 DISTRIBUTION OF CT SCAN PROCEDURES BY ANATOMICAL
AREA
3.2.1 Evolution in the distribution of CT scan procedures over the period studied
Figure 7 below shows the evolution over the period 2012–2018 of the anatomical distribution of CT scan
procedures overall (all ages and sexes). Head and neck scans are by far the most common procedure,
though their proportion showed a downward trend (60% in 2012, 56% in 2018). Procedures on theabdomen and/or pelvis, on the limbs and on the chest and heart had roughly equal proportions, around
10% each. No clear trend for these procedures was observed over the period 2012–2018. Procedureson the spine were stable overall, with a proportion of around 5%. Finally, procedures involving multiple areas(mainly chest-abdomen-pelvis) were the least common, but their proportion seems to be growing steadily.

Proportion of examinations

Group
Head and neck
Chest and heart
Abdomen and/or pelvis
Spine
Limbs
Multiple areas

Year of the procedure

Figure 7: Evolution over the period 2012–2018 in distribution of CT scan procedures according to proceduregroup (anatomical area)

12

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

The distribution of procedures by age group, as shown in Figure 8 below, shows that:among the youngest children (under 6 years), the proportion of head and neck procedures was higher
than for older children, and the overall trend of a decrease in the share of these procedures over theperiod 2012–2018 was not observed. Chest or heart procedures were the second most common inthis population, with a share of 15-20%, which remained fairly stable from 2012 to 2018. All otherareas represented less than 10% of the procedures and show no clear trend;•

among older children (aged 6 years and older), a decrease in the proportion of head and neckprocedures was observed over the period 2012–2018, as for the overall paediatric population (seeFigure 7 above). The other groups of procedures were either stable or slightly grew, representing,each, less than 20% of procedures.

Proportion of examinations

•

Group
Head and neck
Chest and heart
Abdomen and/or pelvis
Spine
Limbs
Multiple areas

Year of the procedure

Figure 8: Evolution over the period 2012–2018 in the distribution of CT scan procedures according toprocedure group (anatomical area), for 4 age groups (under 1 year, 1 to 5 years old, 6 to 10 years old, 11 to
15 years old)

3.2.2 Comparison with evolution in the distribution of MRI procedures
To put the evolution observed for CT scans into perspective, Figure 9 below represents the proportions ofeach anatomical group in relation to the total number of annual MRI procedures. As with CT scans, but in asmaller proportion, procedures involving the head and neck were in the majority in paediatric MRIs with aproportion varying between 40 and 45%, and a decreasing trend over the period studied (compared to 56–
60% for CT scan procedures).
Procedures involving the limbs were the second most represented anatomical group, with a proportion of total
procedures varying between 35 and 40%. This proportion also remained roughly stable annually. The othergroups represented, respectively, about 10% for the spine, 4–8% for the “Other” group7, and less than 5% for
the other groups. The proportion of all these groups of procedures was roughly constant over the period 2012–2018.
The distribution of MRI procedures according to the child age groups, visible in Figure 10 below, does notshow any obvious evolution over the period studied. Head and neck procedures represented theoverwhelmingly majority among children under 6 years of age, and the majority among 6–10 year olds. Among
11–15 year olds, procedures involving limbs predominated.

7

This group consists almost entirely of the CCAM code ZZQN001 - Magnetic Resonance Imaging [MRI] with 6 or more sequences,which is generally used for procedures involving multiple anatomical areas
IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

13Proportion of examinations

Group
Head and neck
Chest and heart
BreastAbdomen and/or pelvis
Spine
Limbs
Other

Year of the procedure

Figure 9: Evolution over the period 2012–2018 in the distribution of MRI procedures by procedure group(anatomical area)

Proportion of examinations

Group
Head and neck
Chest and heart
BreastAbdomen and/or pelvis
Spine
Limbs
Other

Year of the procedure

Figure 10: Evolution over the period 2012–2018 in the distribution of MRI procedures according to proceduregroup (anatomical area), for 4 age groups (under 1 year, 1 to 5 years old, 6 to 10 years old, 11 to 15 years
old)
As the frequency of MRI procedures increased significantly over the period studied, as indicated in paragraph3.1.3 above, it is interesting to compare the frequencies of the different types of CT and MRI procedures
directly, as shown in Figure 11 below. It is clear that most of the growth in the number of MRI procedures isrelated to those involving the head and neck and limbs. It is likely that part of the increase observed for MRI
procedures involving the head and neck is related to a move away from CT scan procedures, although it is notpossible to confirm this based on this information alone.

14

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

CT

Procedure frequency per year
(number of procedures per 1,000 individuals)

MRI

Group
Head and neck
Chest and heart
BreastAbdomen and/or pelvis
Spine
Limbs
Multiple areas
Other

Year of the procedure

Figure 11: Evolution over the period 2012–2018 in procedure frequency (number of procedures per 1,000
individuals) according to the procedure group (anatomical area): CT/MRI comparison

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

15

4. EVOLUTION IN THE TOTAL NUMBER OF CT
SCANS PER CHILD OVER THE PERIOD 2012–2018
The data presented in this section only concern children who were actually exposed to a CT scan, i.e. those
who received at least one CT scan during the year in question. These children are referred to as “patients”
below. The data are therefore annual totals per patient, for each of the years in the period studied.

4.1 PROPORTION OF CHILDREN EXPOSED TO A CT SCAN
The proportion of children exposed to CT scans annually, i.e. the percentage of children who had one or more
CT scans in the year in question, is an indicator that is similar to but different from the procedure frequencies
presented in Part 3 of this report. To illustrate, Figure 12 below shows that, in 2014, the proportion of children
exposed to CT scan was 1.15% (red curve). This means that 1.15% of children, or 11.5 per one thousandchildren (11.5‰), had at least one CT scan in the year. This proportion can be compared with thecorresponding procedure frequency in 2014 for the whole population of children under 16, whether exposed
or not, which is about 14‰ (see Figure 3 above). The difference between these two figures indicates that someprocedures were performed on the same children as part of their medical care.

4.1.1 Proportion, all ages
Figure 12 below shows the proportion of children in the EGB who had at least one CT scan procedure in theyear. This proportion was relatively stable between 2012 and 2018: about 1.1% of children had one ormore CT scans in the year. This proportion was slightly higher for boys (1.14% on average over the period
2012–2018) than for girls (1.04%).
Boy or girl

Boy

Girl

Proportion of children exposed to a CT scan (%)

Sex:Year, with cumulative total

Figure 12: Evolution over the period 2012–2018 in the proportion of children exposed to a CT scan, for girls,
boys and both

4.1.2 Proportion by age group
The proportion of children exposed to CT scan varies with age, as observed in Figure 13 below. Less than 1%of children aged 1–10 years had at least one CT scan in a year, while the figure was around 2% in the 11–15
age group.
The case of children under 1 year old is special: the proportion seems to have increased between 2012 and2018, from about 1.1% to 1.5%. Moreover, the gap between boys and girls seems to be widening: 1.8% vs.
1.1% in 2018. However, these two observations about children under 1 year old must be considered in context
with the statistical uncertainty due to the small number of children under 1 year old in the EGB and the verysmall number of procedures: less than one hundred children under 1 year old had a CT scan procedure, peryear, over the period 2012–2018.

16

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

Proportion of children exposed to a CT scan (%)

Sex:

B/G

B

G

Year, with cumulative total

Figure 13: Evolution over the period 2012–2018 in the proportion of children exposed to a CT scan, for 4 age
groups (under 1 year, 1 to 5 years old, 6 to 10 years old, 11 to 15 years old), for girls, boys and both

4.1.3 Number of CT scan procedures per patient
Figure 14 below shows the average annual number of CT scan procedures per patient, by sex. To clarify themeaning of Figure 14 below with an example: in 2018, out of the population of girls who had one or more CT
scan procedures, the average number of CT scans was 1.2.

Average number of CT scan procedures per patientThis number was relatively stable over the period studied and close to 1.23 CT scan procedures per year. It
was always slightly higher for boys (1.24 on average over the period) than for girls (1.21 on average).

Sex:

Boy or girl

Boy

Girl

Year, with cumulative total

Figure 14: Evolution over the period 2012–2018 in the average annual number of CT scan procedures per
patient, for girls, boys and both

4.2 PATIENTS WHO HAD AT LEAST TWO CT SCAN PROCEDURES IN
ONE YEAR
Figure 15 below shows the proportion of patients who had more than one CT scan in a year. To clarify themeaning of Figure 15 below with an example: in 2016, out of the population of children under 16 who had at
IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

17

least 1 scan, 15% had 2 or more.

Percentage of patients with morethan one annual CT scan

The vast majority of patients had only one CT scan in the year. The percentage of patients who had multiple
CT scans varied between 11 and 16% depending on the year, with no clear trend. The small visible differences
between boys and girls do not seem to be interpretable. Statistical uncertainty should not be ruled out due tothe small number of children and the very small number of procedures (about 100 patients of each sex had
more than one annual CT scan procedure in the EGB).

Sex:

Boy or girl

Boy

Girl

Year, with cumulative total

Figure 15: Evolution over the period 2012–2018 in the percentage of patients having more than one CT scan
procedure per year, for girls, boys and both

18

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

5. EVOLUTION IN CT DOSE INDICES FOR
CHILDREN OVER THE PERIOD 2012–2018
The Diagnostic Reference Level (DRL) system, managed by IRSN in France8, collects paediatric dose data
for some CT scan procedures. Figure 16 below shows the average dose-length product (DLP) values for theprocedures “Brain (10 kg)”, “Abdomen-pelvis (20 kg)” and “Chest (20 kg)” for three different periods: 2011–2012, 2013–2015 and 2016–2018. A clear decrease in dosimetric indices for these three procedures can beobserved: the decreases between 2011–12 and 2016–18 are, respectively, 35% for the brain, 42% for theabdomen-pelvis and 45% for the chest.

Procedure

Average dose-length product (mGy.cm)

Brain (10 kg)
Abdomen-pelvis (20 kg)
Chest (20 kg)

PeriodFigure 16: Dosimetric evolution from CT scans (Dose-Length Product) in children, for 3 anatomical areas (brain
10 kg, abdomen-pelvis 20 kg and chest 20 kg) monitored within the DRL system
It should be noted that the paediatric data recorded in the DRL system are very fragmentary, as the numberof radiology departments that have sent these data to IRSN is very low: 3 in 2011–12 and 10 in 2016–18 forchest CT, 3 in 2011–12 and 11 in 2016–18 for brain and 2 in each of the 3 periods for abdomen-pelvis. The
decreases noted should therefore be considered with caution, but they are nevertheless consistent with the
downward trend in CT dose indices for the adult population (see 2016–2018 IRSN report on DRLs9). The neworder of 23 May 2019 [14] relating to DRLs includes an obligation to send paediatric dose assessments whenmore than 5% of procedures on a given medical device are on children. This regulatory change made it
possible for IRSN, over the period 2019–2021, to obtain a greater number of dose assessments for children
for CT scans than it had in the period 2016–2018. The number of paediatric dose assessments is shown in
Table 1 below: overall, the number of assessments and institutions sending these data slightly more thandoubled between 2016–2018 and 2019–2021. The next IRSN report on DRLs will cover this last period andwill consolidate knowledge of the ionising radiation doses received by children.

8

https://nrd.irsn.fr/

9https://www.irsn.fr/FR/expertise/rapports_expertise/Documents/radioprotection/IRSN_NRD-Report-2016-2018_202009.pdf
IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

19

Table 1: Number of paediatric dose assessments received by IRSN under the DRL system in 2016–2018
and 2019–2021 and number of institutions that sent these data.
Field

Item measured

2016–2018 2019–2021

CT scanNumber of institutions

23

49

CT scanNumber of dose assessments

90

202

All (conventional radiology,
Number of dose assessments
CT scan, nuclear medicine)

305

747

20

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

CONCLUSION
The study conducted by IRSN on exposure of children under 16 years of age to ionising radiation due to CT
scan procedures in France over the period 2012–2018 supplements the previous ExPRI study (ExPRI 2017),
which presented the exposure of the general population to ionising radiation due to diagnostic procedures over
the year 2017 only. As in the ExPRI 2017 study, the data were obtained from the generalist sample panel ofhealth insurance beneficiaries representative of 1/97 of the French population.
Over the period studied, the CT scan procedure frequency was relatively constant (across all ages and sexes),
fluctuating around an average of 13.7‰ per year. For girls, this frequency was slightly lower (12.9‰) and did
not show a clear change over the period studied. The procedure frequency among boys was slightly higher
and seemed to be increasing slightly (+3.8% between 2012 and 2018).
On average over the same period, the CT scan procedure frequency per year varied greatly according to theage of the child: about 15‰ under 1 year old, less than 10‰ between 1 and 9 years old, then increasing rapidly
to reach about 35‰ at 15 years old. Moreover, the CT procedure frequency was significantly higher among
boys than among girls, but with the same trend according to age.
In terms of the anatomical area explored in CT scan, the head and neck procedures were the most common(about 60%) over the period studied. Overall, the proportion of CT procedures by anatomical area was stable
over the period studied. Because of this observation and the common indications between CT and MRI, a
study of evolution in MRI procedures was carried out. Indeed, the recommendations of professionals (inparticular the SFIPP) support transferring certain procedures (e.g. cerebral exploration) to MRI.
This study shows that, unlike in CT, the annual frequency of MRI procedures increased significantly (+59%)
over the period studied, and the frequency was higher for girls. This growth was mainly due to the very rapid
increase in the number of MRI procedures, specifically for the 11–15 age group. As in CT, procedures involving
the head and neck were the most common among paediatric MRI procedures, representing a proportion
between 40 and 45%, relatively stable over the period studied. The second largest category was procedures
involving the limbs, with a proportion between 35 and 40%. However, these procedures represented the
majority for children aged 11–15 years, unlike other age groups where procedures involving the head and neckpredominated.
Concerning the possible transfer of certain CT scan procedures to MRI, it is likely that a part of the increase
observed for MRI procedures involving the head and neck is related to a move away from CT, although it is
not possible to confirm this based solely on the data analysed in the study conducted.
For CT, the proportion of children having had at least one CT scan procedure (exposed children) per year
considered was relatively stable, at about 1.1% for all ages combined, with an average of 1.23 procedures per
exposed child. Among this population of children, between 11% and 16% had two or more CT scans dependingon the year.
Finally, according to paediatric data analysed in the diagnostic reference level (DRL) system managed by
IRSN, the doses received by children for a CT scan (for the brain, abdomen-pelvis and chest) showed adecreasing trend (of -35% to -45%) between the periods 2011–2012 and 2016–2018. However, due to thesmall amount of paediatric data collected during these periods, this decrease should be interpreted withcaution. The new order of 23 May 201910 relating to DRLs includes an obligation for institutions to sendpaediatric dose assessments when more than 5% of procedures on a given medical device are on children.
This regulatory change allowed IRSN to obtain a greater number of dose assessments in paediatrics for theperiod 2019–2021 than in the past, for all types of diagnostic tests. The next DRL review to be published will
cover these three years and will consolidate knowledge of the ionising radiation doses received by children.

10

https://www legifrance gouv.fr/loda/id/JORFTEXT000038529178/
IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

21

GLOSSARYATIH: Agence technique de l’information sur l’hospitalisation (Technical Agency for Information on
Hospitalisation)
BEIR VII: Biologic Effects of Ionizing Radiation, 7th report
CCAM: classification commune des actes médicaux (common classification of medical procedures)
CNAM: Caisse nationale de l’assurance maladie (French Health Insurance Body) (CNAMTS before January
1st 2018)
CNAMTS: Caisse nationale d’assurance maladie des travailleurs salariés (French Health Insurance Body forsalaried workers) (CNAM since January 1st 2018)
CT: computed tomography
DLP: dose-length product
DRL: diagnostic reference levels
EGB: échantillon généraliste des bénéficiaires (Generalist sample panel of health insurance beneficiaries)
EPI-CT: Epidemiological study to quantify risks for paediatric computerized tomography and to optimise
doses
ExPRI: Exposition de la population aux rayonnements ionisants (Exposure of the population to ionisingradiation)
ICRP: International Commission on Radiological Protection
IRSN: Institute for Radiation Protection and Nuclear Safety
MRI: magnetic resonance imaging
MSA: Mutualité sociale agricole (agricultural social insurance mutual benefit fund)
NIR: numéro d’inscription au répertoire national des personnes physiques (national individual registration
number; social security number)
PMSI: Programme de médicalisation des systèmes d’information (Programme for the Medicalisation ofInformation Systems)
RG: Régime général (General scheme)
RSI: Régime social des indépendants (Social security scheme for the self-employed)
SFIPP: Société française d’imagerie pédiatrique et prénatale (French Society of Paediatric and Prenatal
Imaging)
SLM: Sections locales mutualistes (local healthcare mutual fund sections)
SNDS: Système national des données de santé (National Health Data System)
SNIIRAM: Système national d’information interrégimes de l’Assurance maladie (French inter-regime healthinsurance information system)

22

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

REFERENCES[1]
D. Brenner, C. Elliston, E. Hall, et W. Berdon, « Estimated risks of radiation-induced fatal cancer frompediatric CT », AJR Am J Roentgenol, vol. 176, no 2, p. 289‑296, february 2001, doi:
10.2214/ajr.176.2.1760289.
[2]
National Research Council, Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII
Phase 2. Washington, DC: The National Academies Press, 2006. doi: 10.17226/11340.
[3]
J.-C. Nénot, J. Brenot, D. Laurier, A. Rannou, et D. Thierry, « Recommandations 2007 de la Commissioninternationaledeprotection
radiologique
Publication
103
de
la
CIPR
»,
2009.
https://www.irsn.fr/FR/Larecherche/publications-documentation/collection-ouvragesIRSN/Documents/CIPR_103.pdf[4]« Linear No-Threshold Model and Standards for Protection Against Radiation », Federal Register,
august 17, 2021. https://www.federalregister.gov/documents/2021/08/17/2021-17475/linear-no-thresholdmodel-and-standards-for-protection-against-radiation.
[5]
M. S. Pearce et al., « Radiation exposure from CT scans in childhood and subsequent risk ofleukaemia and brain tumours: a retrospective cohort study », Lancet, vol. 380, no 9840, p. 499‑505, august
2012, doi: 10.1016/S0140-6736(12)60815-0.
[6]
J. D. Mathews et al., « Cancer risk in 680,000 people exposed to computed tomography scans inchildhood or adolescence: data linkage study of 11 million Australians », BMJ, vol. 346, p. f2360, may 2013,
doi: 10.1136/bmj.f2360.
[7]
W.-Y. Huang et al., « Paediatric head CT scan and subsequent risk of malignancy and benign brain
tumour: a nation-wide population-based cohort study », Br J Cancer, vol. 110, no 9, Art. no 9, april 2014, doi:
10.1038/bjc.2014.103.
[8]
L. Krille et al., « Risk of cancer incidence before the age of 15 years after exposure to ionising radiationfrom computed tomography: results from a German cohort study », Radiat Environ Biophys, vol. 54, no 1, p.
1‑12, march 2015, doi: 10.1007/s00411-014-0580-3.
[9]J. M. Meulepas et al., « Radiation Exposure From Pediatric CT Scans and Subsequent Cancer Risk in
the Netherlands », J Natl Cancer Inst, vol. 111, no 3, p. 256‑263, march 2019, doi: 10.1093/jnci/djy104.
[10] A. Foucault et al., « Childhood cancer risks estimates following CT scans: an update of the French CT
cohort study », Eur Radiol, march 2022, doi: 10.1007/s00330-022-08602-z.
[11] Institut de radioprotection et de sûreté nucléaire, « Exposure of the population to ionising radiationfrom diagnostic medical imaging procedures in France in 2017- ExPRI 2017 Report », Report n° IRSN
/2020-00564, august 2020.
https://www.irsn.fr/EN/publications/technical-publications/Documents/IRSN_Report-Expri_102020.pdf[12] European Comission, Décret n° 2016-1871 du 26 décembre 2016 relatif au traitement de données à
caractère personnel dénommé « système national des données de santé ».
https://www.legifrance.gouv.fr/jorf/id/JORFTEXT000033702840#:~:text=Le%20pr%C3%A9sent%20d%C3%
A9cret%20fixe%2 0en,ponctuel%20aux%20donn%C3%A9es%20du%20SNDS.
[13] « European Guidance on Estimating Population Doses from Medical X-Ray Procedures - Radiation
Protection N°154 ». https://op.europa.eu/en/publication-detail/-/publication/72d806a2-2fb4-4e4d-a8453b276feed8eb[14] Arrêté du 23 mai 2019 portant homologation de la décision n° 2019-DC-0667 de l’Autorité de sûreté
nucléaire du 18 avril 2019 relative aux modalités d’évaluation des doses de rayonnements ionisantsdélivrées aux patients lors d’un acte de radiologie, de pratiques interventionnelles radioguidées ou demédecine nucléaire et à la mise à jour des niveaux de référence diagnostiques associés.
https://www.legifrance.gouv.fr/loda/id/JORFTEXT000038529178/

Keywords
Radiology, CT scan, paediatrics, medical exposure, ionising radiation, DRL

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

23

TABLE OF ILLUSTRATIONS AND TABLES
Illustrations

Figure 1: CT procedure frequency over one year (number of procedures per 1,000 individuals) according toage of the child (at the time of the procedure), on average over the period 2012–2018. ............................... 8
Figure 2: CT scan frequency over a year (number of procedures per 1,000 individuals) according to thechild’s age (at the time of the procedure) and sex, on average over the period 2012–2018........................... 9
Figure 3: Evolution over the period 2012–2018 in CT procedure frequency per year (number of procedures
per 1,000 individuals) for girls, boys and both. ............................................................................................... 10
Figure 4: Evolution over the period 2012–2018 in CT procedure frequency per year (number of procedures
per 1,000 individuals) for 4 age groups (under 1 year, 1 to 5 years old, 6 to 10 years old, 11 to 15 years old),for girls, boys and both. ................................................................................................................................... 10
Figure 5: Evolution over the period 2012–2018 in MRI procedure frequency per year (number of procedures
per 1,000 individuals) for girls, boys and both. ............................................................................................... 11
Figure 6: Evolution over the period 2012–2018 in MRI procedure frequency per year (number of procedures
per 1,000 individuals) for 4 age groups (under 1 year, 1 to 5 years old, 6 to 10 years old, 11 to 15 years old),for girls, boys and both. ................................................................................................................................... 12
Figure 7: Evolution over the period 2012–2018 in distribution of CT scan procedures according to proceduregroup (anatomical area) .................................................................................................................................. 12
Figure 8: Evolution over the period 2012–2018 in the distribution of CT scan procedures according toprocedure group (anatomical area), for 4 age groups (under 1 year, 1 to 5 years old, 6 to 10 years old, 11 to
15 years old) .................................................................................................................................................... 13
Figure 9: Evolution over the period 2012–2018 in the distribution of MRI procedures by procedure group(anatomical area)............................................................................................................................................. 14
Figure 10: Evolution over the period 2012–2018 in the distribution of MRI procedures according toprocedure group (anatomical area), for 4 age groups (under 1 year, 1 to 5 years old, 6 to 10 years old, 11 to
15 years old) .................................................................................................................................................... 14
Figure 11: Evolution over the period 2012–2018 in procedure frequency (number of procedures per 1,000
individuals) according to the procedure group (anatomical area): CT/MRI comparison................................ 15
Figure 12: Evolution over the period 2012–2018 in the proportion of children exposed to a CT scan, for girls,
boys and both .................................................................................................................................................. 16
Figure 13: Evolution over the period 2012–2018 in the proportion of children exposed to a CT scan, for 4
age groups (under 1 year, 1 to 5 years old, 6 to 10 years old, 11 to 15 years old), for girls, boys and both .. 17
Figure 14: Evolution over the period 2012–2018 in the average annual number of CT scan procedures per
patient, for girls, boys and both ...................................................................................................................... 17
Figure 15: Evolution over the period 2012–2018 in the percentage of patients having more than one CT
scan procedure per year, for girls, boys and both........................................................................................... 18
Figure 16: Dosimetric evolution from CT scans (Dose-Length Product) in children, for 3 anatomical areas(brain 10 kg, abdomen-pelvis 20 kg and chest 20 kg) monitored within the DRL system .............................. 19

TablesTable 1 : Number of paediatric dose assessments received by IRSN under the DRL system in 2016–2018
and 2019–2021 and number of institutions that sent these data.. .................................................................. 20

24

IRSN – CT SCAN PROCEDURES IN CHILDREN IN FRANCE OVER THE PERIOD 2012–2018 AND ASSOCIATED RADIOLOGICAL EXPOSURE

IRSN
Pôle Santé et Environnement
Direction de la SantéService d’études et d’expertise en radioprotection
Emailcontact@irsn.fr
Report No.
Rapport IRSN 2022-00242
All rights reserved IRSN
April 2022

Cover photo:
Philippe Castano/IRSN Media Library31, avenue de la division Leclerc
92260 Fontenay-aux-Roses
RCS Nanterre B 440 546 018

PHONE+33 (0)1 58 35 88 88
WEBSITE
www.irsn.fr

MAILING ADDRESS
B.P 1792260 Fontenay-aux-Roses Cedex

EMAIL
contact@irsn.fr@IRSNFrance